Marquise-cut hematite, 5.45 cts. Photo courtesy of liveauctioneers.com and Jasper52.
Hematite has a long history of use as a pigment. As a gemstone, this material is often carved but very rarely faceted.
Marquise-cut hematite, 5.45 cts. Photo courtesy of liveauctioneers.com and Jasper52.
Hematite has a long history of use as a pigment. As a gemstone, this material is often carved but very rarely faceted.
| Data | Value |
|---|---|
| Name | Hematite |
| Colors | Steel gray to black; blood red in thin slivers or crystals. Massive material is brownish red. |
| Hardness | 5-6.5 |
| Fracture | Even to subconchoidal |
| Cleavage | None |
| Formula | Fe2O3 |
| Etymology | From the Greek hema, “blood,” due to the red streak (powder) and appearance of some specimens. |
| Occurrence | A major ore of iron; usually in sedimentary deposits in thick beds; also in igneous rocks, metamorphic rocks, and lavas (deposited from vapor). |
| Crystallography | Hexagonal (R) (trigonal). Crystals in wide variety of forms, often lustrous or tarnished. Massive; compact; fibrous; reniform (kidney ore); micaceous; stalactitic; earthy. |
| Crystallographic Forms | |
| Refractive Index | 2.94-3.22 |
| Birefringence | 0.280 |
| Optics | o = 3.22; e = 2.94. Uniaxial (-). |
| Optic Sign | Uniaxial - |
| Luster | Metallic, sub-metallic, dull; glistening in micaceous variety. |
| Specific Gravity | 4.95-5.26 |
| Transparency | Opaque |
An “Iron Rose,” a hematite with a rosette crystal shape, from St Gotthard, Uri, Switzerland. © Rob Lavinsky, www.iRocks.com. Used with permission.
Red ochre clay contains hematite. People have used this material since the Stone Age for decoration and writing. More recently, rouge, a polishing compound widely used on silver and gold, is powdered hematite. Of course, people have also mined this mineral as a source of iron.
Ancient Egyptian kohl pot, miniature pestle, and mortar. The pot and mortar are made from marble; the pestle made from hematite. Photo by Fæ, from Wellcome Images. Licensed under CC By 4.0.
The name “hematite” comes from the Greek word for blood. Indeed, some hematites can show red colors, and this mineral also has a distinctive red streak. (See “Identifying Characteristics” below). However, hematites occur in a range of colors, from black and metallic, steel gray to blood-like red in thin slivers or crystals. Massive crystals can have a brownish red color. Most commonly, hematites are black or gray.
Hematite, Elba, Italy. Photo by Gunnar Ries. Licensed under CC By-SA 2.5.
Gem cutters often make cameos, intaglios, carvings, beads, and cabochons from hematites. Occasionally, gem enthusiasts may want these opaque, sub-metallic gems faceted, with flat bases and few facets (like a classic marcasite).
Although reasonably tough with a hardness between 5 and 6.5, hematites are also brittle. As ring stones, use protective settings to shield them from bumps and scratches. Other uses, such as in pendants or brooches, shouldn’t require any special protections.
Hematite’s deep red or brownish red streak is characteristic and diagnostic. A massive material consisting of a mixture of hematite, martite, and gangue minerals occurs near Ouro Preto, Brazil. This granular material has a dark brown, rather than a red, streak.
Although similar in appearance to psilomelane, a manganese oxide, hematite conducts electricity weakly, unlike this lookalike.
Natural hematites aren’t magnetic. However, you may encounter a magnetic material sold as “hematine” or “magnetic hematite.” Despite its name, this material contains no hematite at all. Although these pieces simulate hematites and even have red streaks, their magnetism exposes them.
Gem carvers have made cameos, intaglios, and cabs from hematine.
Hematites occur in most European countries. Much of this material is cut in Idar-Oberstein, Germany but actually comes from England.
Other notable sources include the following:
Cluster of hematites, Bouse, Plomosa District, Plomosa Mts, La Paz Co., Arizona, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.
Massive material is available in very large, solid pieces, good for cutting beads, cabs, etc, of any size desired.
Avoid cleaning hematites with mechanical systems, such as steam or ultrasonic processes. Instead, use a soft brush, mild detergent, and warm water. Consult our gemstone jewelry care guide for more recommendations.
Hematite Necklace. Jewelry and photo by Jennifer C. Licensed under CC By 2.0.
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